AMC1 21L.A.227(c)

• ED Decision 2023/013/R found in: Initial Airworthiness and Environmental Protection (748/2012) Part-21 Part-21L (Jul 2024)

AMC1 21L.A.227(c);(d);(e) Compliance activities for declaring compliance of a major repair design ED Decision 2023/013/R INSPECTIONS AND TESTS In accordance with point [21L.A.227](#_DxCrossRefBm1649098134)(d), the declarant must address the conformity of the test specimen, as well as of the test and measuring equipment. Conformity of the test specimen The recorded justification of the conformity of the test articles is intended to ensure that the manufactured test specimen adequately represents the declared applicable design data. Possible types of non-conformity may be the following: — Non-conformity between the design of the test specimen and the originally intended design data at the time of the test. These are typically identified in the early stage of the test planning, and should be addressed as early as possible (e.g. in the test plan). There may be several reasons for such a non-conformity: to account for interfaces with the test equipment, to conservatively cover several or future design configurations, etc. — Non-conformity between the manufactured test specimen and the design of the test specimen. Such a non-conformity may be the result of the manufacturing of the test specimen. While it is convenient to define any possible non-conformity as early as possible, the declarant does not need to make the distinction between the two types of non-conformity above as long as they are explicitly addressed and justified by cross reference to the test plan or other documents. However, testing for the demonstration compliance with the applicable environmental protection requirements may be conducted in the final design of the product having incorporated the repair design. Compliance demonstration is typically an iterative process in which the design is under continuous evolution. If the aircraft design evolves after the time of the inspection or test, then the final major change design should be checked against the originally intended design (as it was at the time of the inspection or test), and the differences (if any) should be analysed to ensure that the inspection or test results are representative of the final configuration. However, such changes made to the design may lead to the invalidation of the inspection or test results and the need to repeat the inspection or test. It is recommended that the declarant should have a thorough configuration management process to track the evolving design of the major repair. Conformity of the test and measuring equipment: the configuration of the test and measuring equipment should be defined in the test plan and include the following: — definition/design of the test equipment (relevant tools, mechanical parts, electronic components used to execute the test); and — definition of the measuring equipment: — type/model of sensors, together with their technical characteristics; — position and orientation of exciters and sensors; and — electronic measuring equipment (in some cases, this may also include the acquisition and post-processing of data). The configuration of the test and measuring equipment should be defined and controlled through test plans and supporting documentation. The test plan should also include the following elements: — the test cases, methods, and procedures for test execution; — the pass–fail criteria; and — pre-, during- and post-test inspections. The declarant should confirm that the test and measuring equipment conform to its definition in the test plan, and that the sensors and measuring system are appropriately calibrated. Any non-conformity should be assessed, and it should be justified that it will not compromise the test purpose and results. This may be done either in the recorded justification of the conformity of the test articles and equipment or by cross reference to other documents (test minutes of meetings, test notes, etc.). Use of the term ‘adequate’: the test and measuring equipment is considered ‘adequate’ as long as the test execution on the manufactured test specimen (including any non-conformity) and the use of the installed test set-up do not compromise the test purpose and results (for example, by providing better performance than the proposed type design, or by masking any potential failure mode or behaviour). Changes that affect the validity of the recorded justification of the conformity of the test articles and equipment: if changes need to be introduced to the test specimen or to the test and measurement equipment after the justification has been recorded (and before the test is undertaken), then it must be updated. Development versus compliance demonstration tests: sometimes, tests of specimens that conform to a preliminary design, but are not intended for demonstration of compliance (known as development tests), are performed as part of a risk control strategy and to develop knowledge of a subject. Problems and failures found during development are part of the process of increasing the understanding of the design, including its failure modes and the potential for optimisation. Such development tests do not need to meet the requirements of point [21L.A.227](#_DxCrossRefBm1649098134)(d) and (e). Any planned test event should be classified in advance as either a development test or a compliance demonstration test. It is acceptable for a development test to finally form part of the compliance demonstration, and it may be declared afterwards to be a compliance demonstration test as long as it meets the requirements of point [21L.A.227](#_DxCrossRefBm1649098134)(d) and (e). For this reason, it is important to keep the configuration of such tests under control. If the test specimen used for a compliance-demonstration test has already undergone a series of previous tests that may affect or ultimately invalidate its validity due to potential non-conformity to point [21L.A.227](#_DxCrossRefBm1649098134)(d) as required by point [21L.A.226](#_DxCrossRefBm1649097963)(d)(6), this aspect should be considered when justifying the conformity, and specific analyses or inspections may be required to support such a statement. Because of the above aspects, declarants may wish to inform EASA if they intend to conduct a campaign of development tests that may eventually be used as demonstration-of-compliance tests to establish whether EASA would wish to witness the tests. ##### AMC1 21L.A.227(c);(d);(e) Compliance activities for declaring compliance of a major repair design *ED Decision 2023/013/R* **INSPECTIONS AND TESTS** In accordance with point [21L.A.227](#_DxCrossRefBm485231631)(d), the declarant must address the conformity of the test specimen, as well as of the test and measuring equipment. Conformity of the test specimen The recorded justification of the conformity of the test articles is intended to ensure that the manufactured test specimen adequately represents the declared applicable design data. Possible types of non-conformity may be the following: — Non-conformity between the design of the test specimen and the originally intended design data at the time of the test. These are typically identified in the early stage of the test planning, and should be addressed as early as possible (e.g. in the test plan). There may be several reasons for such a non-conformity: to account for interfaces with the test equipment, to conservatively cover several or future design configurations, etc. — Non-conformity between the manufactured test specimen and the design of the test specimen. Such a non-conformity may be the result of the manufacturing of the test specimen. While it is convenient to define any possible non-conformity as early as possible, the declarant does not need to make the distinction between the two types of non-conformity above as long as they are explicitly addressed and justified by cross reference to the test plan or other documents. However, testing for the demonstration compliance with the applicable environmental protection requirements may be conducted in the final design of the product having incorporated the repair design. Compliance demonstration is typically an iterative process in which the design is under continuous evolution. If the aircraft design evolves after the time of the inspection or test, then the final major change design should be checked against the originally intended design (as it was at the time of the inspection or test), and the differences (if any) should be analysed to ensure that the inspection or test results are representative of the final configuration. However, such changes made to the design may lead to the invalidation of the inspection or test results and the need to repeat the inspection or test. It is recommended that the declarant should have a thorough configuration management process to track the evolving design of the major repair. Conformity of the test and measuring equipment: the configuration of the test and measuring equipment should be defined in the test plan and include the following: — definition/design of the test equipment (relevant tools, mechanical parts, electronic components used to execute the test); and — definition of the measuring equipment: — type/model of sensors, together with their technical characteristics; — position and orientation of exciters and sensors; and — electronic measuring equipment (in some cases, this may also include the acquisition and post-processing of data). The configuration of the test and measuring equipment should be defined and controlled through test plans and supporting documentation. The test plan should also include the following elements: — the test cases, methods, and procedures for test execution; — the pass–fail criteria; and — pre-, during- and post-test inspections. The declarant should confirm that the test and measuring equipment conform to its definition in the test plan, and that the sensors and measuring system are appropriately calibrated. Any non-conformity should be assessed, and it should be justified that it will not compromise the test purpose and results. This may be done either in the recorded justification of the conformity of the test articles and equipment or by cross reference to other documents (test minutes of meetings, test notes, etc.). Use of the term ‘adequate’: the test and measuring equipment is considered ‘adequate’ as long as the test execution on the manufactured test specimen (including any non-conformity) and the use of the installed test set-up do not compromise the test purpose and results (for example, by providing better performance than the proposed type design, or by masking any potential failure mode or behaviour). Changes that affect the validity of the recorded justification of the conformity of the test articles and equipment: if changes need to be introduced to the test specimen or to the test and measurement equipment after the justification has been recorded (and before the test is undertaken), then it must be updated. Development versus compliance demonstration tests: sometimes, tests of specimens that conform to a preliminary design, but are not intended for demonstration of compliance (known as development tests), are performed as part of a risk control strategy and to develop knowledge of a subject. Problems and failures found during development are part of the process of increasing the understanding of the design, including its failure modes and the potential for optimisation. Such development tests do not need to meet the requirements of point [21L.A.227](#_DxCrossRefBm485231631)(d) and (e). Any planned test event should be classified in advance as either a development test or a compliance demonstration test. It is acceptable for a development test to finally form part of the compliance demonstration, and it may be declared afterwards to be a compliance demonstration test as long as it meets the requirements of point [21L.A.227](#_DxCrossRefBm485231631)(d) and (e). For this reason, it is important to keep the configuration of such tests under control. If the test specimen used for a compliance-demonstration test has already undergone a series of previous tests that may affect or ultimately invalidate its validity due to potential non-conformity to point [21L.A.227](#_DxCrossRefBm485231631)(d) as required by point [21L.A.226](#_DxCrossRefBm485231459)(d)(6), this aspect should be considered when justifying the conformity, and specific analyses or inspections may be required to support such a statement. Because of the above aspects, declarants may wish to inform EASA if they intend to conduct a campaign of development tests that may eventually be used as demonstration-of-compliance tests to establish whether EASA would wish to witness the tests.